| duc | Action Replay DS Max Save |
| ducf | DinkeyChange Update Code |
| duck | Cyberduck Bookmark |
| dud | DirectUpdate Data |
| duf | DSON User File |
| dum | CODESYS Device User Management Data |
| dup0 | Samsung Kies Duplicate Media Data |
| dup1 | Samsung Kies Duplicate Media Data |
| dup2 | Samsung Kies Duplicate Media Data |
| dupeguru | DupeGuru Duplicate List |
| dus | Readiris Font Dictionary |
| dut | Keysight PLTS Corrected Measurement Data |
| dvc | Dragon NaturallySpeaking Vocabulary |
| dve | Video Toaster Digital Video Effect |
| dvfh | D-Link IP Camera Metadata |
| dvl | Active Safety System Communication Log |
| dvn | Kissock EModel Data Variables |
| dvo | Cook'n Cookbook Recipe |
| dvs | DeepVision Sonar Data |
| dvt | Digital Video Transcript Data |
| dw3 | DeathWatch WebCrawler Data |
| dwe | Creator Waveform Data |
| dwh | Autodesk AutoCAD DWGLOG Log |
| dwi | BrainVoyager QX Diffusion-weighted Image |
| dwk | Autodesk AutoCAD Drawing Lock |
| dwl | Autodesk AutoCAD Drawing Lock |
| dwl2 | Autodesk AutoCAD Drawing Lock |
| dwm | Davis-Wilder Mann Format File |
| dwp | Microsoft Sharepoint Web Part Description |
| dwq | Dreamweaver Saved Query |
| dwr | Dreamweaver Saved Query |
| dws | AutoCAD Drawing Standards |
| dx | JCAMP-DX Format Data |
| dx | Oracle Siebel Transaction Data |
| dx | OpenDX Data |